1. Field of the Invention
The present invention relates to methods of providing weight loss therapy, particularly for patients suffering from major depression.
2. Description of the Related Art
Obesity has been defined in terms of body mass index (BMI). BMI is calculated as weight (kg)/[height (m)]2. According to the guidelines of the U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO), for adults over 20 years old, BMI falls into one of the following categories: below 18.5 is considered underweight, 18.5-24.9 is considered normal, 25.0-29.9 is considered overweight, and 30.0 and above is considered obese (World Health Organization. Physical status: The use and interpretation of anthropometry. Geneva, Switzerland: World Health Organization 1995. WHO Technical Report Series).
The diagnosis of mental disorders is typically based on the criteria provided in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) (American Psychiatric Association; Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), Washington, D.C., American Psychiatric Press, 1994). Three major categories of depression described in the DSM-IV are major depressive disorder (i.e., unipolar major depression), dysthymic disorder (i.e., dysthymia), and bipolar disorder (i.e., manic-depressive illness). There are also several subtypes of these main categories of depression. For example, atypical depression is a subtype of all three main types of depression that is characterized by the capacity to be cheered up when presented with positive events (see id.).
According to the DSM-IV, the essential feature of major depressive disorder is a period of at least two weeks during which an individual experiences a depressed mood or the loss of interest or pleasure in nearly all activities (see id). A diagnosis of major depressive disorder also requires at least four additional symptoms that may include changes in appetite or weight; insomnia; psychomotor agitation or retardation; decreased energy level; feelings of worthlessness or guilt; difficulty thinking, concentrating, or making decisions; and recurrent thoughts of death, suicidal ideation, or attempts to commit suicide (see id).
In contrast, dysthymic disorder is a milder form of depression with symptoms similar to, but less severe than, those of major depressive disorder. Bipolar disorder is characterized by extreme swings in mood between mania and depression, with mania being accompanied by euphoria, grandiosity, increased energy, decreased need for sleep, rapid speech, and risk taking (see id).
Depression has been linked to obesity, with recent studies identifying a specific link between major depression (i.e., major depressive disorder) and overweight or obesity. Depression has also been linked to emotional eating, which in turn is linked to high BMI. Further, depressed patients are known to exhibit weight gain as a side effect of certain depression therapies.
U.S. Pat. Nos. 7,375,111 and 7,462,626 disclose the combination of naltrexone and bupropion for weight loss therapy. Further, U.S. Pat. No. 5,817,665 discloses examples in which the combination of naltrexone and an antidepressant is used to treat depression in individuals who are also obese or crave sweets. However, a need exists for an effective method for the treatment of overweight or obesity in the difficult to treat population of overweight or obese patients suffering from major depression. A need also exists for an effective method to concurrently treat major depression and overweight or obesity.